The present invention relates to the high speed, mass production of cookies, crackers, snacks, and other foods, which have a design or indicia printed thereon. The printing of foods is disclosed in U.S. Pat. No. 4,578,273 to Krubert and Japanese patent publication no. 54-6606 (published Jan. 18, 1979). According to the Japanese patent publication, printing on food or medical and pharmaceutical products using stamp-printing, flexographic printing and silk-screen printing is difficult because the product is likely to change its shape or is likely to be broken. Ink jet printing is used in the process of the Japanese patent publication.
U.S. Pat. No. 4,578,273 discloses that smearing or blotting are disadvantages in spraying or squirting coloring agents upon baked products to form a design, or in using silk screening procedures for imparting designs to cookies and other products. In the process of Krubert, an icing and ink combination is said to avoid blotting and to minimize breaking of the printed surface. The icing mixture forms a hard, non-porous, flat icing surface to which ink is transferred by a silicone pad. The design is contained on an engraved hardened steel flat plate. The ink is applied to the steel plate and squeegeed with a doctor blade to leave the etched ink design remaining on the plate and remove excess ink. The design is removed from the steel plate by contacting the plate with the silicone pad. The printing pads are somewhat domed to prevent the creation of suction upon contacting the hardened icing surface which might otherwise lift the product from mandrels as the pads are retracted after each design element is printed.
In the Krubert process, high speed mass production is limited by the need to retract the pads and the formation of only a single design on each pad. Furthermore, the process requires the use of an icing and a baked dough for applying the printing. The dough is formed by a rotary molder, but after the rotary molded pieces are baked and iced, each cookie is individually manually placed into a moving mandrel.
Printing on individual pieces, as in the proces of U.S. Pat. No. 4,578,273, requires alignment of the individual pieces for proper printing registration. Manual alignment is too limiting for the mass production rates at which multi-zoned band ovens can operate. It is also particularly difficult to align the pieces because they are arranged in rows across the band. Printing on pieces which are arranged in this manner requires registration in the direction of movement as well as transverse to it.
The problem of aligning individual pieces prior to a printing step may be eliminated by printing on a dough sheet. However, the cutting of the sheet into individual pieces must be synchronized with the printed portions. In addition, not all doughs possess the rheological properties for sheetability at high production rates. For example, cracker doughs are generally sheeted before forming the dough into pieces, whereas cookie doughs are often not sheetable at high production rates.
In producing baked goods from a sheeted dough, recycling of dough which remains after cutting of the individual pieces is often used to reduce costs. Extraneous ink transferred to or received on the waste portion of the dough sheet can contaminate or color the waste dough to be recycled. This can contaminate or color the next batch of dough to be formed into a dough sheet.
In the present invention, high speed, high definition printing of baked goods is achieved using a resilient printing roller which can conform to uneven surfaces to be printed upon. The printing can occur at various stages of making baked goods such as cookies, crackers, and snacks. For example, the printing step may take place: i) prior to or after a baking step, ii) before or after cutting a dough into individual pieces from a dough sheet, or iii) after forming the dough into individual pieces by a rotary molder. The printing of each indicia may be in one or more colors.
The cutting of a dough sheet in the present invention is coordinated automatically with the printing step to provide proper alignment and registration of the printed matter with the individual pieces while avoiding extraneous coloring of dough intended for recycling. In addition, the present invention provides automatic alignment for printing on individual pieces arranged in rows, which pieces have been formed, for example, by rotary molding.